The present invention relates to an electrostatic spray gun for powdered material with separate connections for supplying powder and compressed gas, and an intake device for introducing the powder to a conveying gas stream. A spray tube, a spray nozzle and a charging device for electrostatically charging the powder are also provided.
With electrostatic spray guns, a conveying or carried gas with powder particles distributed therein is usually supplied via a hose connection from a stationary injector. They may be portable hand spray guns or automatic guns mounted on a stand.
From the German Utility Pat. No. 7,311,211, there is known a manual spray gun with attached powder magazine. The magazine bottom is formed by a sieve through which the powder is sucked downward into the conveying gas stream. To loosen the powder, there is located above the sieve an agitating vane which is operated by an impeller driven by compressed air. The handling is already cumbersome because the compressed air must be delivered from the bottom end of the handle through a hose to the upper end of the powder magazine. Also, no uniform withdrawal of the powder is achieved in this manner. Regulating the powder supply is just as inaccurate and difficult as guiding the gun and adjusting the other variables. Therefore, it is not possible to ensure with this conventional manual spray gun, a uniform application of the powered material.
It is, therefore, an object of the present invention to provide an electrostatic spray gun of the initially mentioned type with the most universal application so that all variables important to the spraying process can be set quickly, conveniently and precisely, to achieve a uniform powder application with widely varying coating problems.
Another object of the present invention is to provide an electrostatic spray gun of the foregoing character which is compact and may be economically fabricated.
A further object of the present invention is to provide a spray gun, as described, which has a substantially long operating life and may be readily maintained in service.